1. Field of the Invention
This invention relates to processing systems and more particularly relates to optimizing the performance of processing systems.
2. Description of the Related Art
Processing systems respond to increased load with some degree of decreasing performance, or in other words, increases in throughput result in an increase in response time. The relationship between the two variables may appear to be linear at low throughput levels, since unpredictable (Poisson) arrivals can result in queue delays within a processor, router, or other resource. However, once average throughput approaches a limit, occasional bursts will result in more messages being queued, resulting in an increase in the average response time of messages. Consequently, relatively small increases in throughput may result in relatively greater increases in response time.
An unsystematic approach to the performance problem has been to determine a maximum acceptable response time for the system and use that as a limit for maximum throughput. This approach results in system utilization at a point that may be less than optimal. As systems become increasingly complex, the interactions between system components that are not operating at optimum performance can be bottlenecks for the overall system, greatly increasing overall inefficiency, possibly at an exponential rate. Locating and eliminating performance bottlenecks becomes proportionately difficult.
Methods for determining the point of optimum performance have focused on measuring the absolute change in response time for an increase in throughput, using a small number of data points. While this approach can approximate the optimum utilization, a method that utilizes a relative change in response time, using a large number of data points more accurately identifies a point of optimum system performance.